She soon addressed what she was alluding when she announced the split on Twitter later that day.

"Cheating on your loved one is the most hurtful thing one could do. I hate to have to admit, that this relationship is indeed over," she wrote.

On Thursday, Zimmerman, 32, released his side of the story with a lengthy statement posted on his Facebook page that denied any wrongdoing.

"Kat and I split in November and I moved back home to Toronto. During this time, while we were broken up, I did have relations with another woman. Following that, Kat and I reconciled and I acknowledged being intimate with another person while we were estranged," he wrote.

"We did move past those issues and I proposed to Kat in mid-December. At the end of June, it was clear that the relationship was not working and we mutually ended the engagement."

He continues to address Von D's allegations of infidelity. "I was not, at any point, unfaithful to Kat during our time together."

"I don't wish to go tit for tat with these kinds of pronouncements and don't expect to comment further, but I do believe that those who have expressed concern deserve a more complete understanding of what transpired."